Glucose sensors are of great interest for the medical application of blood glucose sensing. Their optimization (in terms of response time, lifetime, sensitivity and selectivity) is highly necessary to improve the treatment of Diabetes Mellitus, a chronic disease affecting millions of 37 people around the world.
Most studies on this subject have involved the use of enzymes. Although enzymatic detection usually shows good selectivity and high sensitivity, the enzyme is easily denatured during its immobilization process.
Non-enzymatic glucose sensors have been studied to develop an effective enzyme-free sensor; in particular the direct electrochemical oxidation of glucose in alkaline medium was investigated at Cu, Ni, Fe, Pt and Au electrodes. Of these electrodes, platinum was the most promising, but it proved to be extremely non-selective and susceptible to poisoning by various components of blood and other physiological media over extended use.
A different approach to the subject involves performing a cyclic-voltammetric study of glucose oxidation at a gold electrode. Using this approach, the occurrence of a positive current peak was observed during the cathodic sweep, and highlighted a highly linear dependence between current value maxima and glucose concentration. The application of the method in blood glucose sensing, however, has been hindered by the presence of inhibitors; chlorides, amino acids, and human albumin were observed to inhibit the reaction. Among them, chlorides are the most problematic because of their high concentration in the blood, (about 0.1 M) and the difficulty inherent in trying to separate them from glucose.
The present invention advances the art by providing new technology for blood glucose sensing to overcome at least some of these problems.